Means to control the effective force of the expanding gases on a fastener, in explosively actuated fastener driving implements



1954 v. R. ,ERICKSON ETAL 2,697,830

MEANS TO CONTROL THE EFFECTIVE FORCE 0F THE EXPANDING GASES ON A FASTENER, LN EXPLOSIVELY ACTUATED FASTENER DRIVING IMPLEMENTS Filed Dec. 29, 1949 I V INVEN'TOR. 703071 15 EZr/ckson' a M W 7 fiza Arm/15y United States Patent NIEANS TO CONTROL THE EFFECTIVE FORCE OF THE EXPANDING GASES ON A FASTENER, IN EXPLOSIVELY ACTUATED FASTENER DRIVING IMPLEMENTS Virginius R. Erickson and Benjamin B. Bullwinkle, Portland, Oreg., assignors to Powder Power Tool Corporation, Portland, 0reg., a corporation of Oregon Application December 29, 1949, Serial No. 135,743

4 Claims. c1. 1-44.s

The present invention relates to stud driving tools of the type employed for installing studs by explosive action in various types of wall surfaces including concrete walls and steel structures, and is concerned more particularly with methods and apparatus for controlling the effective power or force applied to the stud from a standard explosive charge so that the effective force is controlled in accordance with the characteristic of the stud being driven and the characteristic of the surface into which it is to be installed. The present invention provides a variation of the power control methods disclosed and claimed in the co-pending application of Roy Magnuson, Ser. No. 135,114, filed December 17, 1949, and later forfeited, for Stud Driving Tool and Method of Power Control.

In accordance with the instant invention, a standard explosive charge or cartridge is employed but the rate at which the explosive force is applied to the cartridge is controlled to determine the effective force applied to the stud in driving it home into the surface. By selecting the rate of application of the force to a particular stud, in accordance with its characteristics and the characteristics of the surface, a desired effective driving force is obtained.

The above and other objects of the invention are at tained in connection with a preferred embodiment of a stud driving tool as illustrated in the accompanying drawings, in which:

Figure 1 is an elevational view of a stud driving tool which is broken away in part to show the combustion chamber in cross section.

Figure 2 is an enlarged sectional View showing a modified structure for carrying out the invention.

Referring to Figure 1, there is shown a stud driving tool of the character described and claimed in the copending applications of Smith and Daugherty, Serial No. 124,078, filed October 28, 1949, for Stud Driving Tool, and Erickson and Bullwinkle, Serial No. 130,818, filed December 2, 1949 for Stud Driving Tool. In general, stud driving tools of this character are adapted to be separated or broken in two halves for installation of a stud and a cartridge blank. The tool shown has a rear part 10 which contains the various firing control parts, including,

for example, a firing pin carrier 11, and a front or barrel part 12 of the tool including a barrel 13. The barrel 13 is provided with an enlarged rear end 13a which has a threaded connection within the firing pin carrier 11 to connect the two halves of the tool. The barrel 13 is also provided with an enlarged bore in which a breech plug or insert 14 is removably seated. The stud 16 to be driven is mounted in the barrel with its flanged end accommodated in the recessed end wall 14a of the breech plug 14 in which the explosive cartridge 17 is mounted for impact by the firing pin of the firing mechanism.

With the parts disassembled, the breech plug 14 is removed and the selected stud 16 is installed in the barrel, the cartridge 17 is placed in the breech plug 14 and the parts are reassembled as shown in Figure 1 for a firing operation. Firing is accomplished by placing the end of the barrel 13 against the surface into which the stud is to be driven and pressing or telescoping the barrel assembly 12 and the firing pin carrier 11 back into the other part of the tool until a firing position is reached, as disclosed in said applications, and then effecting relative turning movement of the central housing and the end grip to fire the tool. At this time the deflector pad structure 18, yieldablv mounted about the barrel 13, is engaged with the surface about the area of engagement of the end of the barrel so as to provide protection from flying particles of the wall surface upon explosive installation of the stud,

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In accordance with the instant invention, the effective force of the standard cartridge is varied or adjusted to the desired characteristics for installation of a particular stud in a particular wall surface by controlling the rate at which the pressure developed by the gases of combustion are applied to the stud so that a selected effective force is applied to the stud. The terms standard cartridge or standard explosive charge are employed to denote the use of the same selected cartridge for all firing operations so that the same explosive force is available irrespective of type of body or wall surface in which a stud is to be installed, and irrespective of the particular stud being used. This enables a single inventory of cartridges. By varying the effective force of a selected standard cartridge, the tool can be adjusted to the requirements for installing a particular stud in a particular wall surface. As seen in Figure l, the breech plug 14 is provided with an end wall 14a having a restricted orifice 21 therein. Combustion gases are metered through this orifice before becoming effective, so that by selecting a breech plug 14 with an orifice of a desired size, the rate of application of force to the stud is controlled. For maximum effective force the orifice 21 is enlarged to the full diameter of the cartridge. It will be understood that the breech plugs 14 are supplied in sets with orifice sizes related to the various types of studs to be installed and to the various types of surfaces encountered.

Figure 2 illustrates a modified construction in which the breech plug 22 is of standard construction while inserts or discs 23 are provided for interposition between the breech plug 22 and the barrel 13 with orifices 21 of selected sizes in the various discs 23 of a set.

The stud 16 as shown is of the flanged type, however,-

the invention is equally useful with other types of stud, for example, the type which is held frictionally in the barrel.

While we have shown and described certain preferred methods and apparatus for carrying out the invention it will be understood that the invention is capable of variation and modification from the form shown so that its scope should be limited only by the scope of the claims appended hereto.

We claim:

1. In a stud driving tool provided with a barrel having a bore open at the muzzle end and provided with means for mounting a stud, insert means carried by the barrel for free axial sliding movement for installation in and removal from the tool, said insert means having a passage for mounting a cartridge, and a wall included in said insert means disposed between said passage and said stud mounting means and having an orifice therein opening directly into the bore of the barrel for unobstructed communication therewith, and providing a passage for application of explosive gases from a cartridge to a stud.

2. The tool of claim 1 in which said insert means consists of an integral cup-like member having a transverse end wall in which said orifice is located.

3. The tool of claim 1 in which said insert means consists of a sleeve member and a separate disc providing an end Wall in which said orifice is located.

4. In a stud driving tool provided with a barrel having a bore open at the muzzle end of the barrel and provided with means for mounting a stud, a cup-like insert for said barrel mounted therein for free axial sliding movement for installation in and removal from the tool, said insert having means for mounting a cartridge and having an orifice therein opening directly into the bore of the barrel for unobstructed communication therewith and having means for mounting a cartridge, said orifice being disposed between said cartridge and a stud in said barrel.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,030,803 Temple Feb. 11, 1936 2,146,923 Wahlstrom Feb. 14, 1939 2,158,763 Sabol May 16, 1939 2,221,157 Temple Nov. 12, 1940 2,383,053 Fanger Aug. 21, 1945 2,533,851 Temple Dec. 12, 1950 

